ET13 - Puerto Madryn Fm (Miocene of Argentina)

Where: Argentina (42.5° S, 64.3° W: paleocoordinates 42.7° S, 61.6° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Puerto Madryn Formation, Tortonian (11.6 - 7.2 Ma)

• At the top of a 5 m thick complex coquina. Comprises a 200 m thick sequence of coquina, cross-bedded sandstones with mud-drapes, mudstones with heterolithic lamination, and laminated or massive, totally bioturbated mudstones. The age of these deposits has been formerly recognized to be as old as Eocene and early Miocene.

• bed-level stratigraphic resolution

Environment/lithology: shallow subtidal; shelly/skeletal, sandy mixed carbonate-siliciclastic sediments and shelly/skeletal mudstone

• Accumulated during flooding of the Entrerriense or Paranense Sea that flooded a large part of South America during the Neogene. This sequence spans a transgressive-regressive cycle within an overall regressive sequence. It was deposited in a shallow shelf with storm influence, evolving upwards into a tide-dominated estuarine environment
• Specifically from: Complex coquina that grades upwards from scarcely dispersed valves in a sandy matrix to a high concentration of valves in a highly bioturbated mudstone matrix with abundant hash. Formation comprises: coquina, cross-bedded sandstones with mud-drapes, mudstones with heterolithic lamination, and laminated or massive, totally bioturbated mudstones

Size class: macrofossils

Preservation: original calcite

Collection methods: quarrying,

• Unknown repository.

Primary reference: R.A. Scasso, J.M. McArthur, C.J. Rio, S. Martinez, and M.F. Thirlwall. 2001. 87Sr/86Sr Late Miocene age of fossil molluscs in the 'Entrerriense' of the Valdes Peninsula (Chubut, Argentina). Journal of South American Earth Sciences 14:319-329 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 41482: authorized by Austin Hendy, entered by Austin Hendy on 15.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Only includes a portion of the fauna, particularly taxa used in 87Sr/86Sr analyses
Bivalvia
 Pectinida - Pectinoidae
"Chlamys actinodes" = Zygochlamys actinodes
"Chlamys actinodes" = Zygochlamys actinodes Sowerby 1846 scallop
 Ostreida - Ostreidae
Gastropoda
 Sorbeoconcha - Turritellidae
Turritellidae indet. Lovén 1847 turret shell
Bryozoa
  -
Bryozoa indet. Ehrenberg 1831